FDS — Fraud Detection System

S1

Terminal

PIN · card status · limit

real-time

S2

Block rules

Expert if-then · no history

real-time

S3

Score rules

Aggregated features

near real-time

S4 ★

DDM

LR · FFN · AE · IF · W1B · ENS

this demo

S5

Investigators

Review · feedback · labels

offline

Simulate transaction

Amount (£)

Time (s)

7d avg spend (£)

Tx last 24h

Scenario

Account age (d)

Terminal

Override rate

L1/L2 Pre-screening

Status—

Limit—

Rules—

▶ PCA features V1–V28 (advanced)

◈

Simulate a transaction to see detection results

In queue

—

above ENS threshold

True positives

—

fraud caught

False alarms

—

legit blocked

Precision

—

of flagged are fraud

Session: 0 reviewed · — pending · 0 confirmed fraud · 0 dismissed

Flagged transactions — top 100

Sort by:

—

Status: Trigger: Label:

#	Score ▾	Amount	LR	FFN	AE	IF	W1B	Flags	True label	Action

Daily volume

9,500

est. from test scale

Blocked / day

—

Review queue

—

Missed fraud cost

—

ENS threshold

ENS — deployment model ★

▶ Other model thresholds

Cost parameters

FN cost (£)

FP cost (£)

Daily volume

Confusion matrix — ENS

–

True Positive

Fraud caught

–

False Positive

Legit blocked

–

False Negative

Fraud missed

–

True Negative

Legit allowed

Missed fraud / day–

False alarms / day–

Total daily cost–

PR curves — all models

Model comparison at current thresholds

Model	Role	τ	Precision	Recall	F1	R@P0.9	Queue/day	Cost £/day

Cost parameters (FN / FP costs, daily volume) are configured in the Threshold view.

Cost vs threshold — ENS

Investigator queue · Precision@K sorted by composite risk score

Capacity K (alerts / day)100

—

Frauds in K

—

Precision@K

—

Recall@K

—

False alarms

#	Risk	ENS	AE err	Triggered	Label	Decision

Model health

Model	Role	PR-AUC	τ	PSI exposure	Status

PSI — distribution drift

<0.10 Stable 0.10–0.25 Monitor >0.25 Retrain

Drift resilience

Model	PR-AUC	AP early	AP late	Δ (late−early)	Verdict
LR	0.6917	0.8098	0.4413	−0.3684	High drift
FFN	0.7663	0.8183	0.5968	−0.2215	Moderate
D: IF	0.0538	0.1040	0.0149	−0.0891	Weak signal
C: AE	0.0691	0.1204	0.0233	−0.0971	Weak signal
W1B	0.7695	0.8256	0.6006	−0.2250	Moderate
ENS	0.7724	0.8221	0.6142	−0.2078	Most resilient

Terminal attack — Scenario 2 Day 0

Day 0↑ Compromised D8Day 40

Drag slider to simulate.

Terminal risk

Terminal

Override rate